I built and installed my own version of package tora with Oracle InstantClient support using this guide. It has the same version as the package available from standart Ubuntu repository so Synaptic tells me it needs to be updated. I blocked it there, however, apt-get does not know about it and installs the default useless version everytime I do apt-get upgrade. How can I disable such behavior? I guess I should correct the build number of my package but I don't know where to hack sources. My tora version is 2.1.3-2build1.
You need to set the hold flag so that dpkg knows to ignore it. This program should do it http://manpages.ubuntu.com/manpages/hardy/man1/dpkg-hold.1.html " dpkg-hold tora" or the package name if different. Restart then check synaptic is ignoring it before updating though!